Can a hospital force a urinary catheter?

It depends on the circumstances. In some cases, yes.

The answer is actually no. In any person competent to make their own decisions (ie not sanctioned under the mental heath act), the hospital cannot force a catheter and if they do will find themselves in court being sued for battery. There is always an alternative to catheterisation but the hospitals do not make people aware of this as it involves more work and inconvenience for them. They tell you that is some procedures a catheter is essential. This is not true and you can refuse the treatment if they insist it involves catheterisation then refer the matter to the medical council. Dont be misled, catheters are not essential. Its your body, if you dont want one just refuse it, there is nothing they can do.