Different states may have different requirements but here is a quote from the UK AIP ENR 1-7-2 (24 Jan 02) under Altimeter Setting Procedures:-
5.1.4. ....When cleared for climb to a Flight Level, vertical position will be expressed in terms of Flight Level, unless intermediate altitude reports have been specifically requested by ATC.
I would be interested to know what the ICAO Pan-Ops says these days - it's a while since I looked but I suspect it's the same as the UK AIP.
By the way, Galaxy Flyer, point well taken about having a higher TA but it's only 3,000 ft in the UK outside controlled airspace. Go to places like LHR etc. and it's 6,000 ft although the lack of commonality would make good for another thread!