Smeltz, 27, underlined his undoubted importance to Phoenix with the first goal on Sunday to help the club defeat nine-man Newcastle Jets 2-0.

It was goal eight for the Kiwi star this season, who has been tempted away from Westpac Stadium to join Miron Bleiberg's Gold Coast revolution on a three-year deal starting next season.

Hay said Phoenix should have done whatever it takes to convince the German-born striker to stay in the country and could've been upgraded to marquee status to tempt him.

"Upgrading his contract to marquee status is the perfect example. You would have thought that's exactly what they would've done," Hay told au.fourfourtwo.com.

"At the end of last season I know they had the chance to sign him easily but they tried to be a bit clever and say what was a minimal, minimal amount of money.

"When you look back at decisions like that, it's come back to haunt them. I just hope for the sake of the club it doesn't come back to bite them in the butt too much."

In 30 appearances for Phoenix since 2007, Smeltz has scored 17 times. This season, the team has scored 12 times, with Smeltz notching eight with the All-White striker leading the charts with Matty Simon.

Last season, Smeltz finished third in the Johnny Warren Medal vote count and is on track to perhaps better that this year.

Auckland-based Hay, who plays for Waitakere and will face Adelaide United at next month's club world cup in Japan, adds that he doesn't see too many Kiwi players who could take over the mantle of New Zealand's 2007 footballer of the year.

"I like Leo Bertos but I don't see anyone being able to step into Smeltzy's shoes," he said. "Smeltzy's proven week in week out.

"It's a New Zealand team, so we should be trying to promote and better our own best players - but to the New Zealand public, keep them in New Zealand if you possibly can.

"They should've worked so much harder to keep these types of players here. Knowing the game over here, I don't know of any youngsters coming through who could step into his shoes, unfortunately.

"Let's just hope they sign someone with quality [to replace Smeltz]."

But Hay, a former Leeds United and Perth Glory defender who works as a pundit in New Zealand, says the Fred factor can lift the side to an historic first finals series in only its second year

He added: "I put $200 on them at the beginning of the season to make the finals because I liked the look of them.

"I think the confidence will build, They haven't ever won two in a row. I actually think they can sneak up there.

"The thing about the A-League is you just can't pick it week to week. You can't make any money off it if you're a betting man because everyone can beat everyone else.

"Phoenix could go on a run of three or four wins on the trot and they're in."

Hay sees the short time that guest signing Fred from DC United has in the Phoenix camp as the one question mark in this crucial period leading up to Christmas - a period where Phoenix play Victory, Perth and Central Coast at home and take road trips to Suncorp and Hindmarsh.

"Fred, we know he's a fantastic player," he said. "We just hope six weeks is long enough for him to gel on the park.

"Are they going to be able to utilise him as best as possible, give him the ball and is he going to know the runs of Shane Smeltz? Is he going to be able to pick that?

"Still for me, though, the loss of Shane Smeltz then Glenn Moss...losing two of our best New Zealand players from a New Zealand team, that, for me, hurts. I still find that hard to swallow.

"But imagine what Smeltzy will be like at the Gold Coast with even more service - he'll be frightening."