Relay with contact resistance less than 10mohm

I'm updating an old design whitch uses a manual rotary switch to a new one with relay. A small contact resistance is important for me. The rotary switch version has a contact resistance about 3mohm. But I never seen a mechanical relay specified with such small values. Usually, they only give a maximum value such as '< 30mohm', '< 50mohm', '< 100mohm', etc. The working frequency is 50Hz. The current may as low as 1 micro-amp. So, can I safely replace the rotary switch with a relay? Or, there are other better choices?