Furious Steamers captain Colin Bourke believes his team may have been robbed of a potential ITM Cup semifinal.

Bay of Plenty lost yesterday's match against Tasman 41-39 in a dramatic tussle, only sealed when rookie Tasman fullback Tom Marshall potted his eighth penalty goal 3min from time.

It came just 30s after Mike Delany had nailed a 56m kick of his own to cap a monumental Steamers fightback after they were all but penalised off the paddock by referee James McPhail.

McPhail also missed a blatant head-high tackle in the frantic last few minutes, despite advice from his touch-judges, which could have seen the visitors snatch the match.

"This was the first dry track that we've had for a long time and we just wanted to come down here and play a bit of footy and try to get five points," Bourke lamented.

"They were slowing the ball down and everyone could see it apart from the referee and his officials.

"We struck a team that was pretty negative and a ref who was pretty negative in the way he approached the game too - we seemed to be the only ones getting pinged for what they were doing as well."

Bay of Plenty slipped back to seventh on the competition ladder, although their two bonus points earned could yet be crucial.

They're on 32 points, eight behind leaders Canterbury, with Wellington leaping a point ahead after thrashing North Harbour 52-23.

It's put huge pressure on the Steamers to tip over a demoralised Southland team which lost the Ranfurly Shield on Saturday to Canterbury.

This week's match at Baypark is the final home game of the season for the Bay, with only an away match against Northland to come.

While Bay of Plenty displayed their attacking flair with six tries, Tasman turned to the reliable Marshall, who was entrusted with the kicking duties for the first time this season.

He responded by nailing nine of 11 attempts for a personal haul of 26 points to complement his side's three tries as Tasman pocketed just their third win in 11 matches to improve from 13th to 12th on the standings.

They led 27-19 at halftime after playing with a brisk breeze at their backs and continued to benefit from Bay of Plenty's penalty hammering, while first-five Robbie Malneek pierced a hole after a midfield turnover to make it 38-19 in the 55th minute.

Malneek's touchdown served to spark Bay of Plenty into action as replacement backs Grant McQuoid and Daniel Waenga responded with tries within the space of two minutes to slash the difference to seven points with 18 minutes remaining.

McQuoid hit the line on the angle to take a pop pass from Waenga before stepping inside the last defender and Waenga's effort came after a counter-attack featuring dangerous wing Lelia Masaga.

A storming run from No8 Bourke from a scrum outside his own 22 set up Masaga for Bay of Plenty's sixth try in the 70th minute but Delany's failed sideline conversion bid left the visitors two points adrift.

Delany promptly took advantage of the wind to bang over a 56m penalty only to see Marshall immediately respond with his eighth penalty from a much more modest range as Tasman snatched back the lead with 5min to go.

The lead changed hands no fewer than seven times in the first spell alone as Bay of Plenty led 19-15 in the 37th min when halfback Taniela Moa snapped up a fumbled ball from Tasman prop Ben Franks to scamper 40m for his second try.

While Marshall was banging over the penalties, Bay of Plenty responded with five-pointers, as flanker Luke Braid and Moa crossed for tries in the 22nd and 30th minutes.