However, the listed marcoms group said trading in its media and creative agency TTMV would be discontinued as it had "not performed in line with its budgets".
Porta – which in 2014 acquired WSM Print & Design and Digital, Redleaf Polhill, PPS and Publicasity – expects revenue to be "close to 30 per cent" higher than in its previous financial year.
In a trading update this morning, the firm said like-for-like revenue should be around 20 per cent higher and fee income almost 75 per cent higher than the previous year. Adjusted underlying profit (EBITDA) growth is expected to rise by nearer to 35 per cent as it "absorbs the impact of negative currency movements and continues to invest heavily in its future growth".
Porta's PR agency Newgate "experienced a strong year across all jurisdictions", particularly Australia. "Such was the success here that the impact of the weak Australian dollar will affect group profits before tax by approximately £200,000."
Redleaf, which was acquired by Porta in April 2014 and consolidated by the group during the year, "has also been an impressive performer, trading ahead of budgets on a month by month basis".
Porta said PPS and Publicasity have already been integrated into the group head office "and are successfully pitching for new business alongside other parts of the group".
"The board anticipates further strong growth in 2015 throughout the group while margins are also expected to improve with its recent acquisitions operating from one central location."
Porta said the decision to discontinue trading at TTMV came despite a cost recovery programme there. Porta will instead expand its Summit ad agency, which will take on further creative and account management capacity.
Elsewhere in its advertising arm, Porta said 21:12, the financial charities agency formed in January 2013, had "started to gain traction in its core markets and performance is expected to improve in 2015".
Speaking to PRWeek in December, Porta CEO David Wright said he expected Publicasity and its other consumer PR agency Thirteen Communications to merge at some point.
He also said Porta would "definitely" be making further acquisitions, with PR agencies among the priorities.