FRANKFURT (Reuters) - Irish low-cost carrier Ryanair (>> Ryanair Holdings plc) will announce by around late March how much it will step up its service from Lufthansa's (>> Deutsche Lufthansa AG) home hub of Frankfurt, Chief Marketing Office Kenny Jacobs told Reuters.

"We need another six to eight weeks to finish our planning, and then we will announce new routes," he said, adding Ryanair would add routes to new Mediterranean destinations and to cities popular with business travellers.

Ryanair has been working on attracting more business customers. Chief Executive Michael O'Leary told Reuters on Wednesday that the carrier aimed to boost the share of bookings in the "leisure plus" and "business plus" categories to 10 percent from around 4 percent currently within five years.

Ryanair had first announced plans to move into Frankfurt in November, stepping up its push into bigger airports and ratcheting up pressure on Lufthansa, which is expanding its own budget flights.

It started with two aircraft flying to four tourist destinations in Spain and Portugal but had already said it would bolster its offering in winter 2017/18.

"Frankfurt is a strategically important airport," Jacobs told Reuters, adding that fact was not changed by Ryanair's fight against Lufthansa's recent agreement to lease crewed planes from low-cost Air Berlin (>> Air Berlin Plc).

(Reporting by Peter Maushagen; Additional reporting by Victoria Bryan and Conor Humphries; Writing by Maria Sheahan; Editing by Harro ten Wolde)