The station, along with Fairfax Media's other radio assets, merged with Macquarie Radio Network (MRN) last month, with 18 job cuts, including its high-profile presenters, made in the process.

The $200 million deal paved the way for top-rating presenter Alan Jones to start broadcasting on 4BC during the Queensland election campaign earlier in January and February.

Mr Jones has since stayed on, hosting a one-hour midday show. And from next week his breakfast program on 2GB – which continued to dominate ratings in Sydney – will also air in Brisbane.

But MRN chief executive Russell Tate attributed 4BC's gains to its team during the ratings period – which included Ian Skippen, Loretta Ryan, Patrick Condren, Murray Shoring and Walter Williams, all of whom were made redundant – not Jones.

"To be fair to 4BC, he [Jones] has only played a minor part for the last four months," Mr Tate said.

"I don't particularly think about what effect it might have had, but I would expect in the context of one hour per day, it's not going to be a massive impact from Alan."

But MRN's chief operating officer, former Fairfax radio managing director Adam Lang, said Jones helped lift 4BC's ratings.

"Alan Jones is a factor. He is a proven radio star for good reason. His content covers international, national, state and local issues, and his delivery is incredibly compelling," Mr Lang said.

4BC was one of only three commercial stations in Brisbane to grow its market share. It posted the second biggest gain, firming 0.6 percentage points to 4.6 per cent, behind Nova's 106.9 FM, which rose 0.8 points to 11.6 per cent in GFK's second radio ratings survey of 2015,

ARN's 97.3FM continued to dominate the Brisbane market, despite easing 0.3 points to 14.3 per cent.

In Sydney, 2GB shrugged off a 0.4 point drop to 12.6 per cent to win overall ratings. Jones retained the breakfast crown, despite shedding 0.9 points to 15.9 per cent.

Among the FM stations, Southern Cross Austereo's 2Day FM continued its downward spiral, diving 0.3 points to 3.3 per cent. Its breakfast duo Dan and Maz dropped 0.2 points to a fresh low of 2.8 per cent.

2Day has struggled for ratings since the defection of star presenters Kyle Sandilands and Jackie O (Henderson) to rival station, ARN's Kiis 1065, which was Sydney's second top station, firming 0.2 points to 8.9 per cent.

Southern Cross' weakness spread across most markets, relegating the company to third place nationally for the first time.

In Melbourne, MRN won overall ratings thanks to the Fairfax merger, with 3AW firming 1.8 points to 15.4 per cent. The talkback station strengthened its lead in the important breakfast slot, rising 2 points to 20.1 per cent, after No.2 ABC's 774 fell 2.4 points to 14.2 per cent.

The commercial FM stations all finished in negative territory. Southern Cross' Triple M, which was flat at 7.4 per cent, continued its FM dominance. SCA tied with Nova's smoothfm for second at 6.9 per cent, with ARN's Gold third at 6.8 per cent.

ARN's national content director Duncan Campbell said the Melbourne market was a AM story with the FM market yet to settle.

The network recently launched its Kiis brand in the city. That station fell 1 point to 6.1 per cent.

"We're not too worried by it," Mr Campbell said. "It's still a very close, very tight race."