(1) Subject to this Act, where a person ceases to be -
(a) an employed contributor, or
(b) a self-employed contributor,
otherwise than by reason of attaining pensionable age and he has qualifying contributions in respect of not less than 156 contribution weeks, he shall, on making application in the prescribed manner and within the prescribed period, be entitled to become an insured person paying contributions under this Act voluntarily (in this Act referred to as "a voluntary contributor").
(2) The occupational injuries insurance of any person shall be disregarded in determining his right to become, or to continue to be, a voluntary contributor and the rate of voluntary contribution payable in any case shall not be affected by such insurance.
(3) A voluntary contributor shall -
(a) if he becomes an employed contributor, cease to be a voluntary contributor except insofar as is provided in section 22(2), or
(b) if he becomes a self-employed contributor, cease to be a voluntary cont