Mr Forsyth has expressed particular concern that in the last school session only 8 per cent of S1S2 pupils were tested in maths, 9 per cent in reading and 5 per cent in writing. At a meeting with Scottish Office officials last month, the authorities were told such figures were "unacceptable".
Addressing Monday's meeting of the Scottish Grand Committee in Stirling, Mr Forsyth singled out Lothian and Tayside for special criticism.
In the six months between January and June last year, only 14.3 per cent of pupils in Lothian primaries were tested in writing, 26.8 per cent in reading and 26.8 per cent in maths. In Tayside, only 9.42 per cent were tested in writing, 16.7 per cent in reading and 19 per cent in maths. Secondary levels were even lower.
No pupils in Tayside were tested under an agreement with the teachers' unions. In Lothian, only 1.7 per cent of pupils were tested in writing, 1 per cent in reading and 3.5 per cent in maths.
The Scottish Office points out that 45 per cent of pupils should sit national tests in any school session as they complete one of the five levels of the 5-14 programme.
In the primary sector, national figures for the past session show that 45 per cent were tested in maths and 44 per cent in reading, but only 22 per cent in writing, which has long been considered by teachers to be the most time-consuming and difficult area to assess.